cube-js/cube

ClickHouse pre-aggregation WHERE clause loses millisecond precision

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#10326 opened on Jan 22, 2026

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driver:clickhousehelp wanted

Description

Describe the bug When building ClickHouse pre-aggregations with build_range_end that includes milliseconds (e.g., '2026-01-20T23:59:59.999Z'), the generated WHERE clause uses parseDateTimeBestEffort(), which truncates to seconds. This causes the WHERE filter to exclude the intended millisecond boundary.

This is critical for any pre-aggregation with time boundaries that need millisecond precision with explicitly set build_range_end to the end of period.

To Reproduce Build the pre-aggregation for ClickHouse based Cube Observe the generated WHERE clause uses parseDateTimeBestEffort() instead of parseDateTime64BestEffort()

Expected behavior The WHERE clause should use parseDateTime64BestEffort() (or equivalent) to preserve millisecond precision.

Version: 1.6.4 (relevant for previous too)

Additional context In packages/cubejs-schema-compiler/src/adapter/ClickHouseQuery.ts, the dateTimeCast() method returns parseDateTimeBestEffort() when called without a timezone parameter.

Contributor guide

Tech stack
typescriptsql
Domain
backenddatabase
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
under 1 hour
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
TypeScript basicsClickHouse SQL
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
85
Research direction
Modify the dateTimeCast() method in packages/cubejs schema compiler/src/adapter/ClickHouseQuery.ts to use parseDateTime64BestEffort() instead of parseDateTimeBestEffort() to preserve millisecond precision. Ensure the change handles the optional timezone parameter appropriately. Test by building a pre aggregation with a time boundary like '2026-01-20T23:59:59.999Z' and verifying the generated WHERE clause includes millisecond precision.